Apparatus for recovering and controlling the flow of oil in refrigerating systems



Feb. 7, 1933. R. H, BEMAN T -A 1,896,061

APPARATUS FOR RECOVERING AND CONTROLLING THE FLOW OF OIL IN REFRIGERATING SYSTEMS FiledJuly 7, 1930 2 Sheets-Sheet l INVENTOR. fimvsom #0010.

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ATTORN J H. BEMAN ET AL APPARATUS FOR RECOVERING AND CONTROLLING THE Feb. 7, 1933.

FLOW OF OIL IN REFRIGERATING SYSTEMS Filed July 7, 1930 Patented Feb. 7, 1933 UNITED STATES PATENT OFFICE RANSOM H. BEMAN, OF DETROIT, MICHIGAN, AND JOHN H. BENSON, OF SALEM, OHIO,

ASSIGNORS TO MULLINS MANUFACTURING CORPORATION, OF SALEM, OHIO, A. COB- IPORATION OF NEW YORK APPARATUS FOR RECOVERING AND CONTROLLING THE FLOW OF OIL IN REFRIGERATING SYSTEMS Application filed July 7, 1930. Serial No. 468,055.

This invention relates to apparatus for recovering and controlling the flow of oil in refrigerating systems, and has to do more particularly with novel positive acting means for returning oil from the boiler of a flooded type lowside.

In refrigerating systems wherein the oil is allowed to circulate more or less through the system it is obvious that some. of the oil in the crank case of the compressor is pumped over into the evaporator along with the. re-

frigerant. Some provision, therefore, has to be made for the recovery of this oil as otherwise the crank case of the compressor will eventually run dry or substantially dry. Heretofore, provision has been made for re turning the oil from the surface of the liquid refrigerant but a great objection to such systems has been the tendency of the refrigerant to be taken into the suction line when the refrigerant is boiling during the operating cycle. This taking 0 the refrigerant into the suction line results in expanding. of the refrigerant and frosting back between the evaporator and the compressor.

It is the object of the present invention to provide means for positlvely separating the oil from a refrigerant, or the invention can be better explained as relating to a method of purifying the oil and separating the refrigerant therefrom and then returnin it to.

the compressor regardless of the position of the compressor with respect to the evaporator of the condition of the oil in the evaporater. In this case the gist of the operation is the segregating of a certain portion of the top layer of the liquid and the positive removal of any entrapped refrigerant.

Another important step in the method resides in the utilizing of the segregated body of liquid to precool the incoming relatively warm refrigerant. This is accomplished by providing a bafiie plate or a chamber for separating the mixed oil and refrigerant from the main body of refrigerant and arranging this baflle'plate or chamber adjacent the incoming refrigerant conduit. A still further feature has to do with the provision of novel neans for withdrawing the oil from the chamberformed by the bafile plate, irrespective of the position of the compressor. In this case use is preferably made of a Venturi tube arrangement operated by the flow of refrig- "form of baffle plate structure.

Fig. 4 illustrates a modified manner of securing the inlet valve to the float control arm.

Fig. 5 is a side view partly in'longitudinal section of a modified arrangement of baflle plate structure in combinatlop with a Venturi tube refrigerant control.

Fig. 6 is a view similar to Fig. 5 but showlng our novel evaporator unit as used in connection with a high side float.

One of the primary purposes of the present invention is the provision of an auxiliary reservoir 01'' chamber for segregating a limited portion of the oil and combined refrigerant from the surface ofthe liquid in the evaporator. In Fig. 1 this reservoir is generally designated as at 1 and is formed by providing an annular'recess 2 in the header member 3 and by providing a baflle plate 4 for generally separating the main body of refrigerant in the evaporator from this auxiliary reservoir 1.

In the embodiment shown in Fig. 1 the evaporator may be generally designated 5 and the float therefor as at 6. The evaporator may be provided with any suitable header tral a erture 9 which constitutes the inlet condult for the refrigerant. The inlet conduit may terminate in a suitable proJection 10 as best shown in Fig. 1 and the flow of refrigerant through this conduit may be regulated by means of a suitable valve member 11 freely carried by means of a pin 12 secured to the arm of the float 6.

The top portion of the bafile plate 4 is preferably embossed so as to provide a projection 13 which serves as a passageway for the evaporated refrigerant. One or more apertures let are preferably formed in the battle plate as best shown in Fig. 3, so as to normally allow a portion of the oil or combined oil and refrigerant, at the surface of the body of liquid in the evaporator, to flow into the reservoir 1.

In systems where the oil is lighter than refrigerant it will naturally rise to the top of the body of liquid in the evaporator and will, during the operating cycle, have considerable refrigerant mixed therewith. A portion of this oil or mixed oil and refrigerant will be collected in the reservoir 1 and subjected to the heat of the incoming refrigerant passing through the conduit 10. This heat will assist in causing the refrigerant mixed with the oil to evaporate and pass off as evaporated refrigerant through the exhaust valve 8 in the usual manner. The incoming refrigerant passing through the conduit 10 will, of course, give up its heat to the expanding refrigerant within the reservoir and will be materially cooled which will greatly increase the efficiency of the system. The separated oil in the reservoir 1 will readily be drawn into the exhaust conduit in the natural operation of the system. I

Fig. 4 illustrates a modified manner of se curing the valve member 11 to the float arm. In this embodiment two apertures 15 and 16 are formed in the hollow arm and positioned so as to be out of alignment. A suitable pin 17 may then be driven through said apertures 15 and 16 so as to distort the pin and secure the same in place. It will be obvious that a certain amount of resiliency will then be given to the valve plunger.

of arranging the auxiliary reservoir in combination with a Venturi tube member which may be used in connection with the exhaust conduit. This Venturi tube member may be In Fig. 5 we have shown a modified manner of a construction similar to that disclosed in the application of Ransom H. Beman, Serial No. 421,133, filed January 16, 1930. The header may be provided with a suitable inlet port 18and a valve member 19 adapted to receive and cooperate with a valve plunger 12 in the same manner as shown in Fig, 1. A reservoir 20 may be formed in the manner shown and is preferably adapted to carry the float structure in addition to a V enturi tube 21 and an exhaust conduit 22. This exhaust conduit 22 is preferably so arranged as to normally serve as a means for removing the evaporated refrigerant.

The reservoir 20 is provided with one or more apertures 23 which are preferably positioned at a height justabove or at the normal level of the liquld in the reservoir. The position of the aperture or apertures 23 may, of course, vary considerably with diiierent types of cooling units. From the neck of the Venturi tube a small tube 24 projects downwardly into the reservoir 20 and preferably to a point somewhat below the oil level hole 23.

In operation, when violent boiling occurs within the evaporator or when oil is pumped over to raise the level of the liquid to the oil return hole 23, the oil or a mixture of oil and refrigerant will spill over into the reservoir 20. As this oil or mixture of oil and refrigerant flows into the reservoir, it will be placed in contact with the relatively warm conduit 19 and head member 18 whereby the refrigerant will be evaporated and rise to the sure face of the liquid in the reservoir, and if the tube 24 is not submerged it will assist in evaporating the refrigerant from the oil until the residue in chamber 20 contains a small per centage of refrigerant, if any.

This relative difference in temperature is caused by the relatively warm compressed liquid refrigerant which is being drawn into the evaporator. Oil gradually accumulates in the reservoir 20 until it reaches the mouth of a small tube 24 from which point it will be sprayed into the exhaust conduit and due to the difi'erence in pressure across the neck of the Venturi, this oil will be carried back to 'the compressor. The upper part of the reservoir 20 may or may not be open as if it is open the expanded refrigerant gases may pass into the upper part of the evaporator and be drawn oif in the usual manner or if closed the gases will assist in forcing the relatively pure oil from the top of the reservoir into the Venturi tube.

It will be readily understood that the Venturi tube can be designed to take care of various heights of the compressor above the evaporator. In other words, with very small differences in pressure across the Venturi neck it will be possible to draw the oil up to practically' any height that the compressor might be positioned above the evaporator. Therefore it will be seen that when the Venturi tube arrangement is used it is immaterial where the compressor is placed with relation to the evaporator to obtain separation and positive return of the oil without causing a frosting back of the exhaust line between thc evaporator and compressor.

In Fig. 6 we have illustrated the manner of adoptmg'the evaporator and header structure, as shown in Fig. 5, to a refrigerating system of the type having a high side float. It will be understood that the structure illustrated in Fig. 1 may also be utilized in connection with a high side float, the type of structure shown in Fig. 5 being shown merely as one embodiment. In either case, the only to be connected to the inlet port 18 of the evaporator header, such evaporator header being shown in comparatively enlarged section.

In the operation of the structure and system such as illustrated in Fig. 6, the liquid level to be maintained in the evaporator is predetermined in the usual manner, 'as by weighin the liquid admitted to the system or by ta ing in liquid until frosting back when a small amount may be discharged, During the operating cycle of the system, it will be obvious that oil will be entrapped and carried over "into the evaporator with the refrigerant. In the preferred operation of the system the oil is of such specific gravity that it will collect at the surface of the refrigerant in the evaporator as indicated in the heavy dotted lines in Fig. 6. In most instances such layer of oil will undoubtedly have a fairly high percentage of refrigerant mixed therewith. It will be obvious that during more or less violent agitation of the liquid in the evaporator a certain quantity of the oil and refregerant will flow through the apertures 23 and into the reservoir 20.'

continued operation of t e system will cause an accumulation of oil in the reservoir 20 until its level" reaches and envelops the port 24, atwhich time it will be withdrawn through the port back to the compressor so that thereafter there will be a definite flow of oil with a small percentage of refrigerant. As the percentage of refrigerant contained in the oil and reservoir 20 will be relatively low. frosting back in the return line, will not occur. If during any cycle a relatively large amount of refrigerant enters the reservoir 20, it will be lifted or removed by the port 24 until such port is uncovered where upon the refrigerant will be evaporated and returned as gas through the port until the chamber is again cleared of refrigerant.

What we claim is:

1. Evaporator structure for refrigerating systems comprising means for maintaining tially constant level, a small reservoir formed adjacent the main body of liquid in the evaporator, a baflle plate forming a wall of said reservoir and separating the main body of baflie plate for permitting oil or combined oil and refrigerant to pass into the reservoir.

2. Evaporator structure for refrigerating systems comprising an inlet conduit for incoming liquid refrigerant, a reservoir formed partly by the header part of the evaporator and surrounding said inlet conduit, a baflie plate forming part of said reservoir and separating the liquid in said reservoir from the main body of liquid in the evaporator, said bafile plate being so constructed as to allow. a small portion of the surface liquid in the evaporator to be drawn into the reservo1r.

3. Evaporator structure for refrigerating systems including an inlet conduit for a liquid refrigerant and an outlet conduit for conducting evaporated refrigerant to the compressor, and comprising a reservoir, a wall for said reservoir having apertures therein and connecting said reservoir with the liquid within the evaporator at a point adjacent the surface thereof whereby oil and mixed refrigerant flow into the reservoir, a Venturi tube connected to the outlet line for conducting refrigerant gases to the compressor unit, and means connecting the neck of the venturi with the'top portion of the reservoir for positively withdrawing oil therefrom.

4. Evaporator structure for refrigerating systems including an inlet conduit for a liquid refrigerant and an outlet conduit for conducting evaporated refrigerant to the compressor, and comprising a reservoir, a wall for .said reservoir having apertures therein and connecting said reservoir with the liquid within the evaporator at a point adjacent the surface thereof whereby oil and mixed refrigerant flow into the reservoir, a Venturi tube connected to the butlet line for conduct ing refrigerant gases to the compressor unit,

and means connecting the neck of the venturi with the reservoir and extending downwardly into the reservoir at a distance below said aperture or apertures.

n 5. Evaporator structure for refrigerating systems of the pipe adapted to receive and maintain liquid refrigerant at a substantially constant level, comprising an auxiliary reservoir for receiving part of the refrigerant, a Venturi tube for conducting away evaporated refrigerant from above the surface of the main body of liquid in the evaporator, and means'for connecting a portion of the Venturi tube with said auxiliary reser- V011. Y

In testimony whereof we aflix our signatures. v.

- RANSOM H. BEMAN.

JOHN H. BENSON.

liquid in the evaporator and the liquid in the reservoir, and one or moreapertures in said 

